Resistance device



oct. 9, 1934. J. J, MUCHER 1,976524 RESISTANCE DEVICE Filed April 18,1935 Z/ I4 f /z /Z l /4 ,f ff ff ummummmmnnmmmumnu "www" /7 5 MLM( 29 3030 ATToR EY paratively little expense.

Patented ct. 9, 1934 UNITED STATES PATENT ori-ice 8 Claims.

This invention relates to electrical resistance devices, and moreparticularly to an electrical resistance device made up of a number ofxed resistance sections or units, which is especially adapted for use inradio receiving and transmitting apparatus and in other electricalapparatus and circuits requiring one or more fixed resistances.

The invention also has in mind the provision of means for coupling anumber of independent resistance sections or units together into a rigidassemby, forming a multiple resistance device,

each unit being in direct electrical contact with its adjacent unit orunits and the assembly providing a convenient means for centrallylocating or mounting a number of resistance sections or units.

A further object is to provide flexibility in combining differentresistance ranges to constitute the individual resistance requirementsof one' or more circuits.

AThe invention is also particularly useful in repairing burned out orbroken resistances in established circuits where a resistance is to bereplaced and a duplicate of the original cannot be obtained because themanufacturer of the original apparatus has discontinued the manufacturethereof.

The present invention, therefore, provides means for building upindependent fixed resistances from units of standard resistances toproduce a resistance device of the same ohmage as the original unitwhich is to be replaced with com- It has also been customary to buildresistance devices by winding lndependent resistance sections on aninsulated support and to tap off each section with end terminals. Suchresistance devices are objectionable in view of the fact that should onesection burn out it necessitates the replacing of the entire resistancedevice. In the present construction each independent unit while beingelectrically connected to its adjacent unit or units can be readilyreplaced with comparatively little expense. Y

With these objects in view, the invention com prehends a multipleresistance device made up of a number of fixed resistance units, each ofwhich is in electrical contact with its adjacent unit or units, andwhich units are coupled together in end-to-end relation and may thus bearranged or located at a central place in the apparatus.

With these and other objects in view, the invention also resides incertain novel features of construction and arrangement of parts as willbe more fully described and claimed hereinafter. A The invention isshown in the accompanying drawing in which- Figure 1 is a plan view ofthe multiple resistance device embodying the said invention;

Figure 2 is a view in elevation of the resistance device shown in Figure1;

Figure 3 is an end view of the said device; I Figure 4 is a plan view ofone of the fixed resistance units with the metal container andinsulating covering removed to show the resistance Winding and theterminal connection therewith;

Figure 5 is a plan View of the non-conductor core with the resistancewinding thereon;

Figure v6 is a perspective View of one of the end terminals;

Figure 7 is a perspective view of an end member by which the deviceismounted to a support;

Figure 8 is a perspective view of the coupling member for couplingadjacent sections together;

Figure 9 is aplan view of the metal blank which forms the metal sheathor container of a resistance unit;

Figure 10 is a plan view of the insulating member adapted to be wrappedaround the core shown in Figure 5;

Figure 1l is a detailed fragmentary sectional view through Figure lapproximately on the line l11l;

Figure 12 is an end view of the structure shown in Figure 11;

Figure 13 is a perspective view of one of the intermediate terminals;

Figure la is a modified form of resistance unit having two intermediateterminals.

The resistance device l0 illustrated in the accompanying drawingcomprises a plurality of fixed resistance units il, each of which is indirect electrical contact with its adjacent unit or units, adjacentunits being coupled together by a sleeve 12 and the end units beingprovided with an end member 13 having a foot 14 by which the device maybe secured to a base. As

shown in Figure 1, the resistance device 10 comprises three flxedresistance units l1, which are coupled together by two sleeve membersl2, but

yit is to be understood that the said devices may tional area of aresistance wire 16, adjacent convolutions or turns thereof being spaceda predetermined distance so that the said unit will have a xedresistance in proportion to its length. The units 1l are also providedwith end terminal members 17 having a base 18, which are superimposedupon one or more of the turns or convolutions of the resistance wire 16in predetermined spaced relation for each particular length of unit, bywhich each unit of a given length will have the same resistance. Thecore 15, together with the resistance wire 16 and the base 18 of theterminals 17, are covered with a strip of insulation, such as anasbestos sheet which is olled around the same to completely enclose theresistance wire 16 and the base 18, and is folded at the ends, as at 19,to cover the ends of the core 15. A metal containeror sheath 20 forms a.jacket or covering for the unit, this jacket being formed'from a blankas shown in Figure 9, which is cut to form an extension presenting aclamping bar 21, the body of the blank being apertured at 22. When thesaid jacket is disposed upon the unit 11, the opposite edges 23 and 24thereof are arranged in close confronting relation with the clamping bar21 bent to tightly compress or enclose each of the end portions 19 ofthe insulating covering, thus securely enclosing the parts within saidjacket, with the upstanding portions of the terminal members 17 disposedin the recesses 22.

Constructed in this manner the unit 11 constitutes a fixed andindependent section, two or more of which may be built up to form a.multiple resistance device of the desired ohmage resistance to suit therequirements of any particular circuit, it being understood thatthe'units are arranged in end-to-end relation with adjacent terminals 17in direct contact by which the several resistance unitsmay be coupled inseries. For this purpose the terminals 17 have their upwardly extendingportions 25 offset as at 26 in order that the upper ends of adjacentterminals will be in direct contact, the said ends being provided withopenings 27 for connecting the device in an electrical circuit orcircuits.

The sleeves l2 are constructed, as shown-in Figure 8, to slidablyreceive two adjacent units 11 for holding the same in fixed assembledrelation, the coupling snugly engaging the metal container or jacket 20and being provided with a stop 28 punched inwardly from the body thereofto limit the distance the units may be slid into -the coupling.

Instead of the multiple resistance device 10 being made up entirely ofunits 11, the same may consist of one or more units 11 and one or moreresistance units 29 having one or more intermediate terminals 30v spacedas desired between the end terminals 17, as shown in Figure 14. The unit29 is constructed in a manner similar to the unit 11, the resistancewire 31 'being of any desired cross-sectional area and being wound upona non-conductor core 32, adjacent turns or convolutions being spacedapart at predetermined distances to give the desired resistance betweenadjacent terminals. The core 32 is notched at its side edges, in whichnotches are arranged the legs 33 of theI intermediate terminals 30, itbeing understood that the ends of the resistance wire 31 are also woundabout the core 32 beneath the base 34 of the terminals 30.l Aninsulating covering of asbestos or other material is Ialso Wound uponthe resistance wire 31, covering the T5.' base 34 and the ends of thecore 32. A metal jacket or container is applied to this form of unitsubstantially similar to the construction of the jacket 20 for the unit1l, the unit 29 being of a size to be snugly engaged by sleeve members12 for'coupling the same to an adjacent unit similar to the manner ofcoupling the units 11.

For the purpose of mounting the multiple resistance device 10 upon asupport, the end members 13 are provided with a sleeve portion 35adapted to slidably engage the end portion of either unit 11 or the unit29, the body of the sleeve 35 being provided with a foot 14 in oiset orstepped relation by which the same may be secured to the base by meansof a screw or other securing means engaging an opening in the said foot.This construction not only properly supports the various units butspaces the units above the support on which they are mounted, whereby agood cooling action is secured as air may freely circulate completelyaround the device.

As shown particularly in Figures 10 to 12, inclusive, there is provideda suitable insulation for the core 15 with means for clamping theinsulation in place. As illustrated particularly in Figure 10, theinsulation 36 is provided which is adapted to be wrapped around the core15 so as to protect the same on top and bottom, both sides and bothends. As shown in this Figure, the sections 37 and 39 are adapted to befolded over the top of the core 15, while the section 40 is at thebottom of the small sections 41 and 42 to cover the sides. If desired,sections 39 and 37 could be wide enough to overlap, but ordinarily theyare made toabut while the end sections 43 and 44 are made suiiicientlylong to extend acrossthe ends of the core 15 and be folded therebeneathas indicated at 45 in Figure 11. From this figurait will'be seen thatthe terminals 17 have their bottom plates 18 arranged beneath 0the corebut in electrical engagement with the wires 16 thereof. The end flange17', as shown in Figure 6, extends across the ends of the core 15 sothat the remaining part may extend thereabove and through the respectiveapertures 46 in the insulation 36.

By this arrangement the terminals may be easily and quickly mounted andheld rmly in contact with the resistance 16 while being insulated fromall other parts. The metal container or jacket 2O is folded around ontop of the insulation 36 and the ends 21 are bent over as shown inFigure 11, but are spaced from the upstanding portion 25. Thepositioning of the jacket 20 in place and the bending of the partsthereof until they presenta finished structure as shown in Figures 1 to3 results in the terminals being firmly clamped in place so as toprovide not only a good mechanical structure but a good electricalconnection. The complete structure shown in Figure 1, for instance, isknown as a voltage divider, because at each of the terminals current ofdifferent voltage may be taken off. By providing a flexible constructionwhereby any desired number of units may be used, 'the voltage may bedivided with ease as may be desired.

In addition, in case any one unit should become worn out or injured forany reason, it may be quickly removed and another one substituted. Whenthe structure'shown in Figure 14 is used the various resistances arefixed, but under some circumstancesthey are very desirable. In this formof the invention the end terminals are as shown in Figure 11, but theintermediate termipals are as shown in Figure 13 and are clamped 150 inplace by the insulation 36 and by a metal cover similar to cover 20 buthaving suitable provisions for accommodating the intermediate terminals30.

I claimz- 1. A device of the character described comprising a pluralityof resistance units arranged in tandem having terminals at theirrespective ends, each of said units having a metal casing and a metalsleeve slidably tltted over the ends of adjacent units for connectingthe respective units together so that the terminals thereof will be inengagement, said sleeve being resilient and acting not only to keep theadjacent units in alignment but to clamp the ends of adjacent units toprevent accidental disengagement of the respective units.

2. A voltage divider comprising a plurality of independent resistanceunits, each unit having a terminal at each end, each of the terminalsbeing bent at the upper part so as to extend outwardly, and a couplingconnecting the respective units, each of the couplings consisting of ametal sleeve open longitudinally at the top and provided with a centralpressed-up portion for limiting the movement of the unit Within thecoupling so that it will be centered as the terminals of the unitsextending into the coupling contact.

3. A resistance unit formed with a core, a Winding of resistance Wirearranged thereon, a terminal at each end, each of said terminals `havingan L-shaped portion fitting against the end and a lower surface near theend of the core member and overlapping and contacting with a pluralityof turns of said winding, a covering of insulation for the core, saidcovering having apertures through which said terminals extend, saidinsulation covering the bottom, ends and one side of the terminalsexcept the part that projects through the insulation, a metal coveringfor holding the insulation in place and at the same time clamping theterminal against said windings, said metal covering being bent aroundthe core member and its winding, said covering being formed withL a bentover extension at each end forming bars for holding the insulation atthe ends in place and at the same time clamping the terminals inposition and against movement longitudinally of said core.

4. In a resistance of the character described, a resistance unit havinga core and a winding thereon, a terminal at the end thereof, saidterminal having an upstanding contact portion, a iiange fitting againstthe end of said core and a base overlapping said winding, and means forclamping the terminal in position so that said base will press againstcertain turns of said winding, said means including a. coveringinsulation member covering all of the terminals except the upstandingportion and a metal member for clamping the insulation and terminal inposition, said metal member having a portion which straddles theterminal and acts thereon to clamp the terminal against shiftinglongitudinally of said core.

5. A resistance device adapted to combine a plurality of xedresistances, comprising a length of non-conducting material adapted tobe used as a core, a length of resistance Wire Wound over said core,terminal clips positioned in engagement with the ends of said wire, eachof said terminal clips having an upstanding portion, a base fittingflatwise against part of said wire, an insulating covering for said wireand part of said clip, a metal sheathing positioned on top of saidinsulating covering, said metal sheathing acting to clamp theinsulating-material in position as Well as the terminals, said sheathingbeing formed with a plurality of extending members straddling theterminals and pressing the same against the ends of said core.

6. A resistance unit comprising a core of insulating material, a lengthof resistance wire wound over the length of said core, a terminal ateach end of said core, each of said terminals having an upstandingportion and a base, said base extending under the core and intoengagement with the end of said Winding, the upstanding portion beingbent in a direction away from the center of the core longitudinallythereof, a covering of insulating material adapted to cover theresistance Wire and overlap the ends of the core including the lowerpart of the respective terminals, and a metal sheathing for clamping theinsulating material in position and said base tightly against said wire,said sheathing having means at each end extending over the insulation atthe ends straddling the terminals for holding the terminals againstmoving longitudinally of said core.

'7. A voltage divider comprising a plurality of independent resistanceunits, each unit having a terminal at each end, and a metallic couplingslidingly and frictionally connecting the respective units, each of saidcouplings consisting of a metal member open at the top suiiiciently toaccommodate the terminals of adjacent resistance units, each couplingbeing provided with a pressed up portion for limiting the movement ofthe respective units Within the coupling so that the coupling will becentered as the terminals of the units move into contact.

8. A voltage divider comprising a plurality of independent resistanceunits, each unit being provided with la metal casing having a notch ateach end, a. terminal arranged at each end of each unit, said terminalsextending through said notches but out of contact with the metal casing,and a resilient sliding coupling for connecting said uni-ts together endto end, said coupling presenting a sleeve structure extending across thebottom of the adjacent ends of the respective units, across theirrespective edges and partly over the top thereof to frictionally holdthe respective units in alignment and adjacent termina-ls in engagement.

JOHN J. MUCHER.

